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Caption: Douglas-fir stem canker
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Douglas Fir : Stem cankers
(revision date: 4/23/2014)


Biology
Stem cankers on Douglas fir are sunken and oval, occurring on branches or new shoots. Each canker is typically centered around a dead twig and can be small or up to 30" long or more. Cankers result in death of the stem or branch above the point of infection. Young, stressed trees are most susceptible. Infection often occurs following drought, frost damage, or mechanical injury. Two asexual fungi cause the disease. See also Douglas fir: Upper stem canker.
Management Options

Non-Chemical Management
  • Provide proper culture for trees to increase their disease resistance.
  • Avoid injuring trees to help reduce chances of infection.
  • Prune out infected shoots and branches to reduce spread of disease. Make pruning cuts well below cankers. Destroy infected material.
Select non-chemical management options as your first choice!

Chemical Management


None recommended

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Caption: Douglas-fir stem canker
Photo by: Unknown
Caption: Douglas-fir lower stem canker
Photo by: Unknown